When the published form of a pattern seems dated due to new language features or new experiences, it needs refreshing. Unfortunately, just like in spoken languages, once standard definitions are widely circulated in print, it becomes much harder to update them. And instead of updating a single source, pattern authors have expanded and grown the literature. Furthermore, if you're looking for new patterns, want to explore patterns in the making, or want to discuss pattern nuances, print publications aren't your best source. You need to look online. So although some prefer sources of tried and true patterns, ready for immediate consumption, if you only look in published pattern books, you miss out on a lot of design ideas and good discussions.